JackAudio disabled in Blender's OSX official release?
Solved. Blender installer detects missing files related to Jack. I realised this building Blender from the source code. I had to correct the file location of Jack .h files, then it compiled correctly and Jack fully works. This is an issue affecting MacOSX 10.13 + JackOSx 0.92_3. Probably due the fact that Jack is not yet fully supported in newer OSX versions.